Circuit breaker



Nov. 30, 1937. F. B. .JOHNSON 2,190,743

CIRCUIT BREAKER Original Filed Jan. 24, 193]. 2 Sheets-Sheet l ffy. z

WITNEssEs; lNvENToR @MW l @dem Mb/fm. MA1/L71# BY l ATTORNEY Nov. 30,1937. F. B. .JOHNSON 2,100,743

CIRCUIT BREAKER Original Filed Jan. 24, 193) 2 Sheets-Sheet 2 12T f7.2zz Ego? wlTNEssEs; INVENTOR Hede//buE/z/yfon.

www BY WNW t Patented Nov. 30, 1937 PATENT OFFICE CIRCUIT BREAKERFrederick B. Johnson,

Murrysville, Pa., assignor to Westinghouse Electric & ManufacturingCompany, a corporation of Pennsylvania Original application January 24,1931, Serial No.

510,981. Patent No.

2,037,418, April 14, 1936.

Divided and this application March 17, 1936,

Serial No. 69,325

6 Claims.

My invention relates to circuit breakers and more particularly to anarc-extinguishing structure therefor having the capability of openinghigh-voltage, large-current arcs in air or gas.

The circuit breaker of my invention is of the type in which an arc isdrawn and moved into a converging slot in a plurality of spacedconducting plates and split up into a plurality of short arcs. The shortarcs are rotated at a high velocity between the conducting plates byreason of the force exerted upon them by a radial eld set up by coilsbetween spaced groups of the plates.

My invention is a further development of circuit breakers of the typeshown in the copending application of R. C. Dickinson, Serial No.511,010, filed Jan, 24, 1931, now Patent No. 1,927,888, issued September26, 1930, and assigned to the assignee of this application.

rIr'his application is a division of my copending application Serial No.510,981, led January 24, 1931, and issued April 14, 1936 as Patent No.2,037,418.

An object of my invention is to provide an arc extinguisher in which theconducting plates between which the arc is rotated by the radialmagnetic field have an opening therethrough within the radial eld and inwinch the arc may play as a long arc before it is split up between theplates, with means for preventing the short arcs from restriking as along arc through the openings as it is rotated past the opening by theradial field.

This and other objects and advantages of my invention will be madeapparent and more fully understood from the following description of thespecific embodiment of my invention illustrated in the drawings, inwhich Figure 1 is a diagrammatic view, partially in section, of mycircuit interrupter.

Fig. 2 is a sectional View, through the circuit interrupter, takenthrough the deionizing plates on the line II-II of Fig. 3.

Fig. 3 is a sectional View through the deionizing plates, taken on theline III-III of Fig. 2.

Figs. 4, 5, 6, and 7 are side elevational views of the metal plateswhich are assembled to form the deionizing structure, and

Figs. 8 and 9 are elevational views of the sheets of insulating materialwhich are employed to space apart the metal plates.

Referring to Fig. 1, my circuit interrupter II comprises main contactsI3 and I5, which complete a circuit between conductors I1 and I9, and apair of arcing contacts 2l and 23 which are connected in parallel withthe main contacts I3 and I5. Main contacts I3 and I5 and arcing contacts2l and 23 are actuated by any suitable operating mechanism so that themain contacts I3 and I5 are opened rst, with practically no arc, and thearcing contacts 2l and 23 are opened later, drawing an arc which istransferred to a pair of stationary arc horns 25 and 21 by means of themoving arc horn 29 which is attached to the moving arcing contact 23.Stationary arc horns 25 and 21 and the moving arc horn 29 are each madeof magnetic material, such as iron, to cause a more rapid transfer ofthe arc due to the attraction thereof to the iron members caused by thelocal fields set up in the iron by the arc current.

The arcing horns 25 and 21 have arc-terminal portions 3I and 33 andcurrent-conducting portions 35 and 31. The arc horns are each connectedin parallel with the main contacts I3 and I through conductors 39 and 4Iwhich are connected to the outer ends of the current-carrying portions35 and 31. This causes the current to iiow in such direction in each ofthe arc horns that the magnetic reaction between the fields, due to thecurrent in the arc horns and due to the current in the arc, is such asto cause the arc to be moved upwardly on the horns into the deionizingstructure.

The deionizing structure comprises a plurality of groups 43 of maindeionizing plates having coil sections 45 therebetween. The deionizingplates and coils are assembled between end plates 41 and 49 which areelectrically connected to the upper ends of the arc horns 25 and 21. Theplates are secured together by means of a through bolt 5I in aninsulating tube 53 of a brous material impregnated with a condensationresin extending through the deionizing structure. The lower portion ofthe structure is secured together by a pair of tie rods 55 which may beof wood impregnated with a condensation resin having end pieces 51 andwhich support the lower outer edges of the deionizing plates, as shownin Fig. 2.

As shown in Figs. 2 and 3, each of the groups 43 of deionizing platescomprises a plurality of copper plates 59, each of which is surroundedby an iron plate 6I, which is placed in the same plane in edge-to-edgerelation with the plate 59, as shown in Figs. 2 and 7. By having thecopper plates 59 in edge-to-edge relation with the iron plates 6I, heatmay be conducted from each of the copper plates to one of the ironplates, thus adding the heat capacityof one of the iron plates to theheat capacity of each of the copper plates and making it possible to usesmaller copper plates than would otherwise be possible for a structureof the same interrupting ability. Each of the conducting plates 59 has anarrow eXtension 63 extending from the lower end thereof and providedwith a narrow converging slot 65. The slot 95 is symmetrical with themain portion of the plate 59 and has a converging tip 61 which curvesaway from the axis of the plate. Each of the magnetic plates 6| has awide portion 89 surrounding the body portion of the plates 59 and anarrow portion 1| beside the extensions 63 of the copper plates 59.

In order to prevent warping or buckling of the narrow extension 63, suchas would close the slot 65 when subjected to the heat of the arc, eachof the copper plates has a projection 'I3 which extends into a cutoutportion 16 in each of the iron plates 6|. This interlocks the lower endsof the two plates and prevents movement of the narrow extensions 63 outof proper alignment. Each of the 4copper plates y59 is provided with aslot l5 extending from the center thereof to the outer edge to preventthe flow of eddy currents, thereby reducing the magnetic losses.

The'composite plates formed by the iron plates 5| and copper plates 59are assembled in groups, the individual plates of which are spaced apartby the insulating members Tl and I9 shown in Figs.,2yandr9 andinsulating washers 8| around the opening '94 in the center of each ofthe copper plates 59. Copper plates 59 are so assembled that `all of theAplates in each group have the curved portion 6'! of the converging slotcurved `to thesame side of the axis of the plates. The slots 'l5 arepositioned on opposite sides of adjacent plates throughout each group,thus eliminating the continuous opening through the stack in which thearc could play, which would result if 'the slots 'l5 were on the sameside of all of the plates.

The insulating sheets 11 and 'I9 may be of iish paper and so shaped asto provide an annular path 83 in which the arc is rotated. Theinsulating spacers Tl and 'I9 have depending portions 85 and 89 whichdefine a narrow arc path 9| along the slot 65, and a curved portion `93which leads the arc into the annular path 83 along a tangent thereto.Insulating spacers 'l1 have 'projections 89 which extend over the tipsof the slots 67 and prevent the arc from striking back Ythrough `theslots on each revolution of the arc, as it rotates across the tops ofvthe slots. As shown in Fig. 2, the insulating lspacers Il and I9 aremade of such width that they over-lap the jointjbetween the conductingplates 59 and the magnetic plates 9| adjacent to the path over which thearc is moved. This prevents the possibility of the jarc playing in thejoints between `the plates. Each insulating sheet I9 has a projection 91defining the upper portion of the annular path and leaving a Ventilatingopening 99 leading from one side thereof.

Above the extension 91, is provided a rapidly Ydivergingventilatingpassage |0| in which the arc `gases 4may expand and come into contactwith large lsurfaces of bothV the iron and copper plates,

lwhereby the gas is rapidly cooled andions are re-V moved therefrom.

The arc horns 25 and 27 are formed of spaced sheets of iron havingVentilating passages |03 therebetween. The Ventilating passages |03permit the 'flow -o-f gas out of the end of the stack ahead ofthe arcasit is moved upwardly on the arc horns and also permit upward ventilationthrough the stack after the arc has been moved into the spaces betweenthe deionizing plates. It is thus seen that a continuous ventilatingpassage is provided from the lower end of the arc chamber through thewhole deionizing stack. This allows a through flow of gas to .rapidlycool the arc and the plates 59 and 6| so that the heat of the arc israpidly dissipated, which allows the circuit interrupter to be used forinterrupting heavy currents with a duty cycle, which calls for a largenumber of successive interruptions of the circuit.

The insulating plates 'Il and 19 are assembled in such relation to thecopper plates 59 that the curved tips 6l of the slots 65 are aligned,and the direction of rotation of the arc around the annular path 83 issuch that the motion of the arc adjacent to the Ventilating opening 99is in the opposite direction to the iiow of gases out of the passage.This prevents the arc from being blown out of the annular path into theVentilating passage by reason of the flow of gas through the stack.

The arc is rotated around the annular path 83 by the action of a radialmagnetic eld set up by radial field coils |95 which are spaced betweenadjacent groups 43 of deionizing plates.

As shown in Fig. 1, the directions of the fields, as indicated by thearrows |01, are opposite in alternate groups 43 of deionizing plates.The arc is, therefore, rotated in Vopposite directions in alternategroups of deionizingplates. The positioning ofthe conducting plates 59and the insulating spacers 'Il and 19 is, therefore, reversed inalternate groups, as is indicated by the broken lines in Fig. 2.

Each of the magnetizing-coil sections 45 comprises a radial eld coil |95which is placed between a pair of coil-end plates I 99, as shown inAFig. 5. Each end of each coil |95 is electrically connected to one ofthe coil-end plates |99. At the lower end of each coil-end plate |99 ispositioned a coil-end transfer plate which is spaced from the coil-.endplate |99 by a gap H3.

Each coil-end transfer plate has a converging slot ||5 therein whichextends to a point slightly below the gap H3. Each plate |09 has a holel? through which the bolt for securing the plates together is passed,and a slot ||9 for reducing eddy currents. Y

A number of transfer plates l2! are positioned between the coil-endtransfer plates ll! below each of the radial eld coils |95. Each` of thetransfer plates |2| has a converging slot |23 similar to the slots I5 incoil-end transfer plates l i l. The transfer plates are spacedapart byinsulating spacers |25 of fish paper which have a narrow portion l2'.lto form a path in winch the arc is moved and an enlarged circularportion |29 at the upper end of the passage |27.

At each end. of the stack of plates and radial field coils is an endplate |3| which is electrically connected in the circuit to beinterrupted. Plate ISI has an opening |33 for the through bolt 5h and acoverging slot |35 similar to 'the slots |23 and H5, as shown in Fig. 4.Y

As shown in Fig. 2, slots ||5,which are aligned with slots |23 and |35,are shorter and inwardly tapered at a more rapid rate than slots 55 inplates 59. As the arc is moved up into the aligned slots in all cf theplates, the are is irst eonstricted in the tips of the slots l l5, |23and |35 while still in a relatively wide portion of the slots 55. Thearc is then transferred to the coil-end transfer plates I| I and'transfer plates I2|, splitting the arc into a plurality of short arcsbetween transfer plates |2| and a plurality of arc sections betweenplates I I I. Each of the arc sections may be freely moved into thestack because of the width of the slots 65. As the plurality of sectionsof the arc are moved upwardly, they cross the gap H3 between thecoil-end plates |09 and coil-end transfer plates HI. The voltage dropthrough the radial coils I 35, connected between the plates |09, issmaller than that necessary to maintain the series of arcs between thetransfer plates |2| so that the arcs therebetween are extinguished, andthe current flows through the radial field coils |05. Since the arc ismoving in relatively wide portions of the slots 65 at the time that itcrosses the gap H3, there is not much resistance to its movement so thatit crosses the gap H3 without serious burning of the coil-end plates|03.

As the arc is moved farther, the slot 'B5 gradually converges so thateach of the arc sections is concentrated into an arc of high currentdensity and small cross section. The arc is then above the narrowextensions 1| on the magnetizing pla'tes 6| so that it is no longeracted upon by the blow-in elcl but is within the much stronger eld setup by the radial coils |05 which provide a field of such strength thatthe arc may be rapidly moved along the tips 61 of the slots 65 and splitbetween the plates 6|. This use of the radial field for splitting eachsection of the arc into a plurality of short arcs is advantageous inthat it is not necessary to provide a blow-in field of such strength asto provide the force necessary to split the arc into a plurality ofshort arcs. The arc then enters tangentially into the annular path 83and is rapidly rotated until the occurrence of the zero point on thealternatingcurrent wave when it is extinguished.

As shown in Figs. 1 and 2, a plurality of iron laminations |31 areprovided to form extensions of the iron plates 6| beside the arc-drawingcontacts and arc horns. The iron laminations |31 are spaced apart bysheets of fish paper |39, shaped similar to the iron plates |31. Thelengths of the laminations |31 are varied in different sections of thedeionizing structure. The end sections |4I are made of such length as toextend to the arc horns 25 and 21. The section |43 adjacent to thearcing contacts 2| and 23 and main contacts I3 and I5 are made longerthan the other sections so as to extend to a point adjacent to thecontacts to blow the arc into the deionizing structure. The intermediatesection |45 is of a length between those of the other sections so as toextend beside the moving arc horn 29. The provision of iron laminations|31 provides an iron path for the flux set up by the arc current as soonas the arc is drawn, in order to move the arc into the deionizingstructure in cooperation with the flux set up by the current iiowing inthe arc-terminal portions 3| and 33 of arc horns 25 and 21. The edges oflaminated members |31 are protected from the arc by libre plates |41having arc-resisting inserts |49 of asbestos or other suitable material.An insulating sheet of iish paper I 59 is placed in the joint betweenthe lower edges of the deionizing plates and the iron laminations |31and also extends between the laminations |31 and fibre plates |41. Theiron laminations |31 and fish paper spacers are secured in the structureby being clamped between wood blocks |5| and the fibre plate |41.

A static shield is provided in the form of a pair of sheets |53 ofinsulating material, such as a fibrous material impregnated with acondensation resin and having sheets of tinfoil |55 embedded therein.

From the above description it is seen that my invention provides an aircircuit breaker which is capable of interrupting large currents at highvoltages in a most effective manner.

While I have described a specific embodiment of the invention, it shouldbe understood that the various novel features thereof may be used invarious combinations, and I am not to be limited by the specificdescription except as indicated by the scope of the following claims.

I claim as my invention:

1. In an arc extinguisher, a plurality of spaced plates each providing apath about which the arc may be rotated, an opening through said platesin which the arc may play, means for moving the arc from said openinginto said path, and means for guiding the arc past said opening as itrotates and preventing it from moving into the opening.

2. In an arc extinguisher, a plurality of spaced plates of conductingmaterial each providing an annular path for the arc, an opening througha plurality of said plates in which the arc may play as a long arc,means for moving the arc from said opening into the plates, therebysplitting it into a plurality of short arcs, and rotating the short arcsabout the annular paths, and means of insulating material for guidingthe short arcs past the opening through the plates as they rotate andpreventing the arcs from restriking through the opening as a single longarc.

3. In an arc extinguisher, a plurality of spaced plates of conductingmaterial each providing an annular path for the arc about which the arcmay be rotated more than a whole revolution, a

coil for setting up a radial magnetic iield across said annular arcpaths, an opening through a plurality of said plates of conductingmaterial, said opening having a portion within said radial magneticfield, means for causing an arc to play in said opening, and means ofinsulating material for guiding the short arcs past the opening throughthe plates as they rotate and preventing the arcs from restrikingthrough the opening as a single long arc.

4. In an arc extinguisher, a plurality of members of conducting materialbetween which the arc may be split up into shorter arcs, said conductingmembers each providing a recurrent path about which the short arcs maybe rotated, a coil for causing a magnetic field for rotating the arcs,an opening through a plurality of said members of conducting material,means for causing an arc to play in said opening, said opening having aportion within the magnetic field for rotating the arc, and insulatingmeans around said opening on the side thereof which is approached by thearc as it rotates to prevent the arc from moving into the opening as itrotates around the recurrent path.

5. In an arc extinguisher, a plurality of spaced plates of conductingmaterial each providing an annular path for the arc about which the arcmay be rotated more than a whole revolution, a coil for setting up aradial magnetic iield across said annular arc paths, an opening througha plurality of said plates of conducting material,

said opening having a portion within said radial magnetic field, meansfor causing an arc to play in said opening, and said coil beingenergized while the arc plays in said opening in a plurality CII of saidplates whereby the radial magnetic -eld set up by the coil moves the arcfrom the opening into the plates and splits it up into shorter arcs andthen rotates the shorter arcs around said annular paths on theconducting plates, and means of insulating material for guiding theshort arcs past the opening through the plates as they rotate andpreventing the arcs from restriking through the opening as a single longarc.

6. In an arc extinguisher, a plurality of members of conducting materialbetween Which the arc may be split up into shorter arcs, said conductingmembers eaoh providing a recurrent path about which the short arcs maybe rotated, a coil for causing a magnetic field for rotating the arcs,an opening through a plurality of said members or conducting material,means for causing an are to playin said opening, said opening having aportion within the magnetic eld for rotating the arc, said coil beingenergized while the arc plays in said opening through a plurality ofsaid members of conducting material whereby said magnetic field causedby the coil for rotating the arc is effective for moving the arc fromsaid opening and causing it to'be split up into shorter ares betweensaid members of conducting' material, and insulating means around saidopening on the side thereof which is approached by the arc as itrotatesto prevent the arc from moving into the opening as it rotatesaround the recurrent path.

FREDERICK B. JOHNSON.

